Technical Field
The present invention relates to an inkjet image forming apparatus and to a cleaning method therefor.
Background Arts
A cleaning operation is done as one of cleaning operations in an inkjet image forming apparatus in order to keep proper ink injections from inkjet heads. In such a cleaning operation, (1) a purge process in which inks are forcibly injected from ink injection surfaces of inkjet heads, (2) a wipe process in which dusts attached onto the ink injection surface is wiped out by a wiper blade or the like together with inks remained on the ink injection surface is done, and (3) a flush process in which mixed inks staying in nozzles are forcibly injected out, are done sequentially.
A Patent Document 1 (Japanese Patent Application Publication No. 2000-233518) discloses an “ink jet recoding apparatus” that includes inkjet heads for forming dots on a record medium by injecting ink droplets from nozzles according to print data. In a flush process of the ink-jet recoding apparatus, flush conditions are changed with respect to each of the nozzles in order to do flushing (cleaning) efficiently. The flush conditions are changed by changing an amount of ink injected from each of the nozzles.
For example, in the flush process of the ink-jet recording apparatus, a nozzle that injects ink having larger thickening rate (increase rate of viscosity) is controlled so as to injects a larger amount of ink in order to recover an injection capability sufficiently.